"DIK" (bracelet, indistinct, unlabeled) transform of 1,2,3,4,...

Terms

a(0) =1a(1) =3a(2) =6a(3) =13a(4) =24a(5) =51a(6) =97a(7) =207a(8) =428a(9) =946a(10) =2088a(11) =4831a(12) =11209a(13) =26717a(14) =64058a(15) =155725a(16) =380400a(17) =936575a(18) =2314105a(19) =5744700a(20) =14300416a(21) =35708268a(22) =89359536a(23) =224121973a(24) =563126689a(25) =1417378191a(26) =3572884062a(27) =9019324297a(28) =22797540648